"While bird flu vaccinations can provide partial protection against certain strains, the vaccinated chickens can still be infected by other strains, particularly since free-roaming chickens have contact with other wildlife," he said.

Moreover, according to The Straits Times, Dr Koh added that the chickens will reproduce, and the chicks would not be protected by the same inoculation.

He said that the Agri-Food and Veterinary Authority (AVA) will enhance its management of animal populations, including free-roaming chickens, through research studies and public engagement efforts.

Dr Koh was replying to Mr Louis Ng (Nee Soon GRC), who wanted to know whether AVA would consider vaccinating free-ranging chickens against bird flu instead of culling them.

In January, AVA culled chickens in Pasir Ris and Sin Ming in response to noise complaints and to safeguard public health, drawing flak from the public.

Dr Koh had told Parliament earlier that AVA is conducting a study with the National University of Singapore (NUS) to better understand the ecology and population of selected bird species here, one of which is the free-ranging chicken.

On Tuesday, Dr Koh also gave the assurance that AVA will involve stakeholders like academics, wildlife experts, the community, and animal welfare groups in exploring various approaches and solutions.